A deburring installation, briefly named deburrer, is combined with or installed after a continuous steel casting installation for removal of cutting burrs (2) developed by a thermochemical longitudinal or cross cutting of strands, the deburrer having cylindrical deburring pistons (4) or tiltable deburring caps (25) which are placed in a rotatably supported deburring body (3) and pushing the cutting burr (2) off by a rotating movement of the deburring body (3).
During cutting with oxygen, especially in continuous steel casting installations, there arise more or less big burrs, which develop at the two lower cutting edges, consisting out of a mixture of brittle iron oxides and hard to elastic steel, at the beginning and the end of each workpiece (1) because of the down flowing and partly cooling cutting slag. Parts of those burrs hang down deeply from the edges like icicles, other parts form relatively flat bulges at the edges of the lower work piece surfaces, otherwise there are all kinds of compositions of both. The form and material composition of all cutting burrs (2) depend on the casting and cutting procedure. In any case those burrs are very disturbing in the further processing, if not already for the further transport. It would be most desirable to avoid such cutting burrs (2) but this cannot be realized. Under certain circumstances a considerable minimization is possible but cannot be predicted with certainty.
As a consequence there exists a number of methods of operation and procedures in order to remove the burrs as soon as possible after their formation, namely, by: melting respectively scarfing by oxygen burners; stricking-off respectively chiselling-off by hand; mechanical knocking-off with quickly rotating, hammer-like tools; mechanical shearing-off with fixed or horizontally swinging, shear blade-like tools; mechanical shearing-off with linearly moved, piston-like tools.
While the scarfing type deburring procedures mainly show the advantages of high deburring speeds, they have considerable disadvantages like fume formation, slag splashes, granulation water requirements as well as the danger of fire and explosion. Therefore the demand turns more to mechanical deburring possibilities where besides of the costs for mechanical equipment and energy only the considerable time requirements and the discharge of the deburred burrs have to be considered.
A reliable and successfully working deburrer is described in EPA 90 11 20 27.9. For the first time this deburrer applies individually operated deburring pistons (4), which are supported in a deburring body (3) and can adapt to vaulted workpiece surfaces and thus considerably improves the deburring success. However, this installation is also costly and does require intensive maintenance; the exchange of the deburring pistons (4) is difficult and time-consuming. Furthermore burrs from longitudinal cutting and of more complicated cross sections cannot be removed at all or only with a lot of difficulties.
The deburring machine according to EP 0 671 230 A1 shows a considerable improvement because the deburring pistons (4) are no longer individually supplied with high pressure compressed air but are supported in a deburring body (3) which is designed as a tube-type body. The whole so-called deburring body (3) is pressurized via an air pipe, so that all deburring pistons (4) lift at the same time. With this solution it is important that the pressure is considerably lower than with the first mentioned installation and that the deburring pistons (4) press against the lower surface of the workpiece (1) following its shape using the lifting movement of the deburring body (3), which is produced via simple lifting cylinders (30) before every deburring procedure.
In contrast to the before describe deburrer the deburring piston (4) does not contact flatlyxe2x80x94which means in an angle of 90 to the workpiece (1)xe2x80x94but only with one edge because of a slight tilting of the deburring body (3). Thus the contact pressure and as a consequence the pressure in the deburring body (3) can be considerably reduced. Moreover a safer because limitated contact of the protuding, sickle-shaped cutting blade is achieved without being influenced by eventual roughness of the lower workpiece surface and subsequently a smallest shearing force.
In addition the design of the deburring pistons (4) allows to install them all from the same side which reduces the maintenance requirements considerably.
Nevertheless the still existing great disadvantage is that the working movement during the deburring procedure, which means the relative movement between deburrer and workpiece (1), can be produced in only two different ways.
It is possible to design a stationary machine and thus allowing a relatively simple construction, with the result that the deburring of the front work piece side in flow direction requires a time-consuming return movement of the workpiece (1).
Or the deburrer is designed as travelling installation with the result of higher cost and the disadvantage of increased space requirements. This explains the poor application of such installations in multiple strand installation for smaller sizes (i.e. billets).
Further development requirements result from the fact that the deburring of strands which were cut longitudinal in flow direction is extremely complicate, as they can only be treated sectionwise and not continuously with such a machine.